Discuss as:

Feds sue Arizona's Sheriff Joe Arpaio, alleging racial profiling

Matt York / AP

Maricopa County Sheriff Joe Arpaio.

Escalating a long-running battle with the outspoken sheriff of Maricopa County, Arizona, the Justice Department on Thursday sued him, his office and the county over civil rights issues involving racial profiling.

"The police are supposed to protect and serve our communities, not divide them. This is an abuse of power case," said Tom Perez, the head of the Justice Department's Civil Rights Division.

"If you look Latino, you are fair game," he said.

The county has refused to impose a program, proposed by the Obama administration, that would train deputies on how to make traffic stops without improperly targeting Latinos. "They're telling me how to run my organization. I'm not going to give up my authority to the federal government," Sheriff Joe Arpaio said Wednesday before the lawsuit was filed.

The Justice Department claims that since 2006, Maricopa County sheriff's officers unfairly have targeted Latinos for traffic stops -- unlawfully detaining, searching and arresting people, many of whom turn out to be US citizens or legal residents.

The lawsuit claims that the Sheriff's Office discriminates against jail inmates who have trouble speaking English. Commands are issued only in English, and when prisoners who don't understand them fail to comply, entire areas of a jail are put in lockdown, inciting "obvious hostility," Perez said.

He said Latino jail inmates are also forced to sign English-language legal documents in which they forfeit key legal protections.

A third category of improper conduct, the lawsuit says, involves retaliation by the Sheriff's Office against perceived critics, including judges, lawyers, and community leaders.

"They have been subject to actions designed to silence and punish them, including wrongful arrests and baseless lawsuits," Perez said.

More content from msnbc.com and NBC News:

Follow US News on msnbc.com on Twitter and Facebook